The US Centers for Disease Control and Prevention report that the number of cross-borne diseases is rising at a record pace, while the geographical area of ticks continues to grow. Lyme disease is the most well-known tick-borne disease, but other diseases such as ehrlichiosis and STARI have been discovered and the list of tick-related diseases continues to grow.
Tick bites have even been shown to cause allergic reactions to red meat in some people.
Is a heating climate responsible for this growing threat? Should we expect more ticks and tick-related diseases this year because the last winter was hot and wet? And how do we protect ourselves against ticks?
I interviewed Matthias Leu, an ecologist and adjunct professor at the College of William & Mary, to find answers to these questions and learn more about cross-prevention. The interview is below.
Q: Does the weather affect thick populations? Eg. Does a warm winter lead to more rafts, or does a cold winter lead to smaller rafts?
A: So far we have not found an association with weather and cross populations. Many people believe that cold winters kill ticks. If that is true, why do fleets live in northern states like Minnesota and Wisconsin? What affects the threshing population is the amount of deer and mice available as hosts to ticks.
Q: The Washington area has seen a growing deer population in recent decades. Has the tick population increased in direct proportions?
A: Yes, urbanization has led to a growing population of deer and mice being used by the ticks for blood meals, and this in turn increases the bitch population. Flowers and shrubs planted by homeowners feed the deer well.
Q: Has chewing-gum disease increased, and does the weather affect the spread of these diseases?
A: Yes, cross diseases have increased and a tick – especially born disease, ehrlichiosis, is affected by the weather. Ehrlichiosis, which produces symptoms similar to the Lyme disease, is transmitted to humans by Lone Star ticks feeding on fawns or other hosts such as rabbits and squirrels. Adult deer have stronger immune systems that keep ehrlichia bacteria in control, but fawns carry much more of the bacteria. During cold winters, when the number of fawns is likely to be lower, the bacteria are not as prevalent as lowering the disease rate. The opposite is true in the warm winters.
Q: Is the spread of the Lyme disease affected by the weather?
A: The bacteria causing the Lyme disease are transmitted by black bone feeds on white-lined mice bearing the bacteria. The bacteria are the causative agent of Lyme disease. It has been shown that the bacteria are more widespread after warm winters and springs, and also in mast years, where echoes are abundant. The acorns are a food source for the mice, which helps increase their number and thus increase the disease rate.
Q: I understand you harvest rafts every year in Southeast Virginia. Have you found that the number of fleets has increased from year to year?
A: We found the number of ticks fluctuating greatly from year to year, and there is much movement of ticks related to the location of their primary food source, deer and mouse. We just have to make our 2019 cross harvest, so I'll get these results soon.
Q: I have heard of people who develop meat allergies from threshold bites. Can you explain?
A: Yes, alpha-gal syndrome occurs when a carpet bites a human and sends a carbohydrate that it received while feeding on another mammalian host. In some people, the alpha-gel carbohydrates trigger an immune system reaction when they eat read meat, which can be quite serious. There is no treatment for alpha-gal syndrome except to avoid red meat.
Q: How do you recommend keeping cross-free when going through forests or fields?
A: I have found DEET does not work well for ticks, but permethrin works very well. I spray my clothes with permethrin and let them dry for 24 hours. Rafts will die upon contact with the sprayed clothing. Clothing can now be purchased pre-treated with permethrin.
Q: How do you recommend removing ticks when they have bitten?
A: I use tweezers to grasp the fix's head as close to the skin as possible. When I have a firm grip, I pull the junction straight out and avoid twisting the tip of the tip. This should ensure that the cross head does not remain embedded in the skin.
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While a warming climate will provide beneficial living conditions for ticks, it is also the population's explosion of deer and other mammals living around us that influence the spread of cross-borne diseases.
Urbanization and fragmentation of forests has brought many of these animals and their coughed fleets directly into our backyard. Fleets are found near their hosts, and the spread of cross-borne diseases occurs in many areas that have both hot and cold climates.
Some cross-borne diseases, including the Lyme disease, are more common in hot conditions. A study published in the fall found for a future warming of 3.6 degrees (2 degrees Celsius), "The number of Lyme disease cases in the United States will increase by over 20 percent over the coming decades."
More research is needed to fully understand the interaction between weather and cross / host distribution.